Why is my battery draining so fast on my Galaxy Tab S?

[berger321]

Battery is jumpy and unpredictable on Galaxy tab s 8.4

I recently got this tablet and the battery life suddenly drains from say 70% to 30% instantly and proceeds to drop at a normal rate afterwards. When it runs out and shuts down, i can then restart it without charging and it will bring me back to 50%

Please Help!!!!

Thanks

ps. I cant return it because i rooted it and im not sure if they will take it back. Also the problem was around before the root

 

[Golfdriver97]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

Welcome to the forums. Can you post screenshots of the battery use please? Settings>Battery, show the list and tap on the graph to show that too.

 

[Rukbat]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

I'm guessing (it has to be a guess if I can't test the tab myself) that it's a defective battery, and your only recourse is to remove all traces of rooting it and ask wherever you bought it if they'll replace the battery. (Unfortunately, if it's not under warranty, you'll probably be paying $50 or more in labor to replace what should be about a $25 battery (and probably be paying 2 or 3 times that for the battery itself). Batteries are considered consumables, and even batteries that are factory defective are almost never replaced under warranty.

 

[berger321]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4



here are the screenshots. I hope they come through

 

[berger321]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

Its very strange. Ive had quite a few android devices and this has never happened.
It there anyway to reset knox to 0?
i hear triangle away works but is it compatible with my device?

Thanks for the help!!!

 

[Golfdriver97]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

Here are a couple problems...you have a wakelock, and your mobile signal is really weak. Both of those are very likely contributing to the excessive drain. Since you are rooted, install wake lock detector and charge the tablet. See what that reports. As for the mobile signal, put the device in airplane mode, then turn your WiFi on again. That should help.

Sent from an AOSP M8

 

[berger321]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

Ok thanks
ill try that

 

[Rukbat]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

Those hits to zero tell me that the battery is throwing dendrites, shorting it out internally. (It comes with the technology - the industry is working on a way of making lithium batteries that don't throw dendrites.) It doesn't happen often, but when it does, there's nothing you can do but replace the battery (or put up with the shorts).

In addition to what Golfdriver said, install Greenify (and Xposed Installer) and hibernate all the apps that don't have to run by themselves (Phone, Messages, email if you want emails pushed to you, any alarms, etc.) That'll give you a lot less Awake time. (I look at Wakelock Detector once in a while, but since almost everything is "Greenified", just about nothing that shouldn't be waking the phone does. My Awake line, for a period I'm not using the phone, is almost completely black.)

It there anyway to reset knox to 0?

Sorry, no. The Knox flag is a write-once bit. Once you get 0x1 it stays that way. (Even Chainfire has confirmed that it can't be reset, and he probably knows Samsung phones as well as most of the engineers working at Samsung.)

 

[berger321]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

Ah right thanks!!
So dendrites are a hardware problem (it sounds like) so even if my tablet is rooted they should still take it back shouldn't they?

 

[Rukbat]

Re: Battery is jumpy and unpredictable on Galaxy tab s 8.4

No. Even if the phone isn't rooted, a bad battery isn't usually covered under warranty, it's considered a consumable (like the gas in the tank when you buy a new car). You could try to unroot it, then bring it back and ask for a new battery or replacement tab (bring a picture of the graph, showing the voltage dropping to 0 in 0 time, which is indicative of an internal short), but don't be surprises if they tell you that no matter why the battery failed, it's not covered. (Then again, you may be surprised and they may replace it. I've had a couple of batteries replaced for dendrites in a couple of decades in the business. It's not the usual way they do things, but sometimes you get lucky.)